The present invention relates generally to dynamoelectric machine assemblies and more specifically to such assemblies having unique spatial relationships vis-a-vis between phase insulators.
A dynamoelectric machine stator assembly normally comprises a magnetic core having a bore, axially extending slots, and windings comprised of one or more coils formed by one or more turns of magnet wire conductors. The winding turns have side turn portions which are disposed within axially extending slots, and end turn portions which project from the slots and are disposed about end faces of the core. The conductors employed in forming the plurality of coils are provided with an electrical insulating coating to prevent short circuiting between adjacent turns, and each slot usually contains electrical insulation which may be, for example, a slot liner in order to prevent grounding of the windings to the stator core. Because winding phase to winding phase voltage potentials can be appreciable (that is, more than line voltage and even substantially more so when capacitors are interconnected with the windings, the end turn conductor portions of one winding are often separated or insulated from the end turn conductors of another winding by additional insulation which is variously called "phase" insulation, "window" insulation, "ladder" insulation, "H" insulation, or "between phase" insulation. Without additional insulation, only the wire enamel or insulation prevents arcing and failure when the turns of one winding phase contact the turns of another winding phase; and the appreciable voltage potential between such turns can both shorten the life of the conductor insulation and/or cause insulation failure.
In addition to the end turn "phase" insulation, the side turn portions of different winding phases are often additionally insulated by what are known as insulating "wedges", slot "separators", or "separator wedges" disposed within the slots of the core at positions to separate side turn portions of one winding from the side turn portions of another winding.
The end turn portions of different windings often are compacted and could intimately touch each other, especially when such end turn portions are subjected to blocking or pressing operations to obtain a particular end turn silhouette or configuration. Depending on the degree of compaction, the provision of end turn phase insulation and placement of the same may be of substantial importance.
Historically, end turn phase insulators have usually been placed on a stator core by a hand operation. When a hand insertion or manual insertion technique is employed, the phase insulators must be individually disposed or mounted (that is, one at a time) on the stator core which adds considerable time and expense to the stator assembly fabrication process. Such a manual insertion operation may require three or four operators inserting end turn phase insulators in order to keep pace with automated stages of a stator assembly fabricating operation. Thus, it would be desirable to develop methods and apparatus for disposing end turn insulators on a core which would reduce the time and labor expense, and which could be employed to dispose a plurality of insulators substantially simultaneously.
Another known approach for disposing end turn phase insulation is to dispose the phase insulators essentially simultaneously with the insertion of multiple windings into the stator core. For example, the end turn phase insulators are disposed between two windings while the windings are on coil injection equipment and then subsequently inserted substantially simultaneously with the two windings. However, insertion of end turn insulators with two or more windings may create a problem of bunching together of the windings and the end turn phase insulators and thus, causing either a hang-up in the insertion equipment resulting in downtime of the operation or the need for an additional operation wherein the end turns are pried apart to straighten the insulators disposed therebetween.
The difficulty of inserting end turn phase insulators simultaneously with the windings may be increased when the windings are inserted individually, i.e., by utilizing multiple passes of the coil injection equipment. It is often desirable to have a maximum slot fill or maximum number of conductor turns within the slots of the core in order to maximize motor efficiency and material utilization. In obtaining maximum slot fill, it is often desirable to insert each winding individually with an intermediate distributing operation being used between insertion operation of the different windings so as to distribute the side turns of a previously inserted winding within particular areas of the slots containing such side turns. Such individual winding insertion and intermediate distributing techniques tend to minimize the forces required for inserting the windings into the core and thus, eliminate problems of winding damage which may occur with elevated injection forces. However, individual winding insertion can create problems of inserting or disposing end turn phase insulators. The insulators can no longer be disposed between two windings for insertion, but rather must either trail the first to be inserted winding or lead the second to be inserted winding. If an end turn insulator is disposed on coil injection equipment so as to trail a first to be inserted winding, the insulator may be damaged by the stripper of the injection equipment as it strips the coils of the winding from the injection equipment into selected slots of the core. On the other hand, inserting an end turn insulator with the second to be inserted winding requires that the insulator lead the second winding during the insertion process. When the insulator leads the second winding, the insulator no longer has winding turns to cushion it against surfaces of the core teeth and thus, may be damaged by sharp edges or protrusions along the core surfaces.
Therefore, it is desirable to have end turn phase insulator inserting techniques which minimize the time and labor involved with individualized hand insertion techniques; and techniques which minimize end turn disposing problems incurred when windings are individually inserted into a core. It also is desirable to have end turn phase insulator disposing techniques that are independent of the winding insertion operations and thus alleviate problems of coil injection equipment downtime and the scrapping of winding material resulting from injection equipment hang-ups. Such techniques are claimed in the application from which this applciation is divided.
A general object of the present invention is to provide new and improved dynamoelectric machine assemblies having unique end turn phase insulator spatial characteristics.